Is the Human Food Chain Collapsing? Some Researchers Say 'Yes.'

This is the sort of trend or prediction that any author or screenwriter should be aware of, at least in my opinion.

We as a species have a fascination with potential disasters dating from the days of Dante's Inferno and earlier.  Why do we find such possibilities so intriguing?  From future wars to natural disasters to the Christian Second Coming to zombies to ecological disasters, it seems that books and movies dealing with worst case scenarios find a ready market.


In fact, one of my favorite novels is Nevil Shute's 1957 "On The Beach", a book that chronicles the last days of a small group of Americans and Australians waiting to die after global nuclear war.  Adapted by writer John Paxton, a film version of the story starring Gregory Peck, Ava Gardner, Fred Astaire and Anthony Perkins was released in 1959.

The way Mr. Shute handled the topic was to focus on the people involved, with very little in the way of catastrophe suitable for big screen special effects.  It's doubtful the movie could be made today without the addition of extraneous fight scenes or spectacular images of mass death and destruction.

Getting back to a potential food chain collapse, ecologists and nutritionists have for years preached about the food chain that starts with microscopic bacteria and algae that supports the nutrition of the rest of planet.

In short, microscopic organisms of the ocean are dying out, threatening our very existence.  Gloom and doom?  Perhaps, but certainly a prospective reality that should be explored in fiction or film.  If you can figure out how to include some overwhelming images.

Here's the report, with a link to the original study for those who care to pursue the topic further.

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Global marine analysis suggests food chain collapse

Species collapse from the top of the food chain down.

A world-first global analysis of marine responses to climbing human carbon dioxide emissions has painted a grim picture of future fisheries and ocean ecosystems.

Published today in the journal Proceedings of the National Academy of Sciences (PNAS), marine ecologists from the University of Adelaide say the expected ocean acidification and warming is likely to produce a reduction in diversity and numbers of various key species that underpin marine ecosystems around the world.

"This 'simplification' of our oceans will have profound consequences for our current way of life, particularly for coastal populations and those that rely on oceans for food and trade," says Associate Professor Ivan Nagelkerken, Australian Research Council (ARC) Future Fellow with the University's Environment Institute.

Associate Professor Nagelkerken and fellow University of Adelaide marine ecologist Professor Sean Connell have conducted a 'meta-analysis' of the data from 632 published experiments covering tropical to artic waters, and a range of ecosystems from coral reefs, through kelp forests to open oceans.

"We know relatively little about how climate change will affect the marine environment," says Professor Connell. "Until now, there has been almost total reliance on qualitative reviews and perspectives of potential global change. Where quantitative assessments exist, they typically focus on single stressors, single ecosystems or single species.

"This analysis combines the results of all these experiments to study the combined effects of multiple stressors on whole communities, including species interactions and different measures of responses to climate change."

The researchers found that there would be "limited scope" for acclimation to warmer waters and acidification. Very few species will escape the negative effects of increasing CO2, with an expected large reduction in species diversity and abundance across the globe. One exception will be microorganisms, which are expected to increase in number and diversity.

From a total food web point of view, primary production from the smallest plankton is expected to increase in the warmer waters but this often doesn't translate into secondary production (the zooplankton and smaller fish) which shows decreased productivity under ocean acidification.

"With higher metabolic rates in the warmer water, and therefore a greater demand for food, there is a mismatch with less food available for carnivores ─ the bigger fish that fisheries industries are based around," says Associate Professor Nagelkerken. "There will be a species collapse from the top of the food chain down."

The analysis also showed that with warmer waters or increased acidification or both, there would be deleterious impacts on habitat-forming species for example coral, oysters and mussels. Any slight change in the health of habitats would have a broad impact on a wide range of species these reefs harbour.

Another finding was that acidification would lead to a decline in dimethylsulfide gas (DMS) production by ocean plankton which helps cloud formation and therefore in controlling Earth's heat exchange.

Related stories:

• Ocean acidification
• Around a quarter of the CO2 that humanity emits into the atmosphere is ultimately dissolved in the oceans. Here it forms carbonic acid, altering ocean chemistry and decreasing the pH of the surface water. This increased acidity reduces the amount of available carbonate ions, an essential 'building block' used by many marine species for shell and skeleton formation. Beyond a threshold concentration, this rising acidity makes it hard for organisms such as corals and some shellfish and plankton species to grow and survive. Losses of these species would change the structure and dynamics of ocean ecosystems and could potentially lead to drastic reductions in fish stocks. Compared to pre-industrial times, surface ocean acidity has already increased by 30 percent.  Unlike most other human impacts on the marine environment, which are often local in scale, the ocean acidification boundary has ramifications for the whole planet. It is also an example of how tightly interconnected the boundaries are, since atmospheric CO2 concentration is the underlying controlling variable for both the climate and the ocean acidification boundaries, although they are defined in terms of different Earth system thresholds.
• Are marine ecosystems headed toward a new productivity regime?
• Carbon dioxide pools discovered in Aegean Sea
• Climate change reduces coral reefs' ability to protect coasts
• Commercial Food Fish Moving Away From Tropics
• Global sea levels have risen six meters or more with just slight global warming
• Ocean acidification may cause dramatic changes to phytoplankton
• Overfishing and the Survival of Us
• Pacific reef growth can match rising sea, study suggests
• Phytoplankton and zooplankton biomass are expected to decrease by 6% and 11% respectively by the end of century due to climate change

Story Source:  Materials provided by University of Adelaide.  Ivan Nagelkerken and Sean D. Connell. Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions. Proceedings of the National Academy of Sciences, October 12, 2015